Method and materials for making color photographs from color positive print stock

ABSTRACT

A METHOD OF DEVELOPING COLOR POSITIVE RELEASE STOCK IS DESCRIBED TO PRODUCE A COLOR POSITIVE IMAGE. THE DEVELOPMENT PROCESS MAKES IT POSSIBLE TO EXPOSE THE COLOR POSITIVE RELEASE PRINT STOCK IN A CAMERA DIRECTLY TO AN ILLUMNATED SUBJECT, AND THEN BY SUBJECTING THE EXPOSED COLOR POSITIVE RELEASE PRINT STOCK TO THE DEVELOPMENT PROCESS, A FIXED COLOR BALANCED COLOR POSITIVE IMAGE RESULTS. THE DEVELOPMENT PROCESS INVOLVES REDUCING THE SENSITIVITY TO REACTION OF ONE LAYER CONTAINING METAL HALIDE TO RESTRAIN DEVELOPMENT ACTION IN A REDUCER DEVELOPER SOLUTION, WHILE INCREASING THE SENSITIVITY TO REACTION OF OTHER LAYERS CONTAINING METAL HALIDE TO ACCELERATE THEIR DEVELOPMENT ACTION IN THE REDUCER DEVELOPER. A REDUCER DEVELOPER CONTAINING METAL HALIDES TO MODIFY THE SPEEDS OR SENSITIVITY DURING DEVELOPMENT IS DESCRIBED.

United States Patent O "ice METHOD AND MATERIALS FOR MAKING COLOR ISPFSEOGRAPHS FROM COLOR POSITIVE PRINT Gerald D. Sadick, Round Hill Lane, Sands Point, N.Y., and Edward Palmonka, 226 Fieldmere St., Elmont, N.Y. 11003 No Drawing. Filed May 2, 1968, Ser. No. 726,248

Int. Cl. G03c 7/02 US. CI. 96-22 2 Claims ABSTRACT OF THE DISCLOSURE A method of developing color positive release stock is described to produce a color positive image. The development process makes it possible to expose the color positive release print stock in a camera directly to an illuminated subject, and then by subjecting the exposed color positive release print stock to the development process, a fixed color balanced color positive image results. The development process involves reducing the sensitivity to reaction of one layer containing metal halide to restrain development action in a reducer developer solution, while increasing the sensitivity to reaction of other layers containing metal halide to accelerate their development action in the reducer developer. A reducer developer containing metal halides to modify the speeds or sensitivity during development is described.

The invention relates to the art of color photography and more particularly concerns a method of making color positive images from color positive release stock or film without the use of color negatives.

This invention relates to an improved process for developing exposed color film.

BACKGROUND Heretofore in making color photographs it has been accepted procedure to expose color negative film in a camera to obtain color reversed images. Then the exposed color negative film is used to print true color photographs on color positive print stock. It has not been possible to use conventional color positive release print stock as color film in a camera heretofore for the following reasons:

Conventional color positive photographic print release stock or film has three metal halide layers on an acetate support base. The bottom layer contains silver halide and is most sensitive to blue light. This layer is the most sensitive of the three. The middle layer contains silver halide and is most sensitive to red light. It is less sensitive than the bottom silver halide layer. The top layer contains a silver halide and is sensitive to green light. The top layer is less sensitive than the lower two layers. When this multilayer color positive release print stock or film is exposed in a camera to a subject illuminated in daylight, or with blue light in the range of 4,000 to 5,000 angstroms the response of the bottom layer to the blue light is greater than would occur if the color positive release film were exposed behind or underneath color negative film. During subsequent color development in reducing solution for any given development time more silver reduces in the silver halide layer at the bottom than in the two upper layers. Too little silver halide is then left to react in a subsequent color developer solution to form yellow dyes. As a result,

3,597,198 Patented Aug. 3, 1971 the final color photograph made from the color positive release print stock is off in color balance. It is so deficient in yellow dye that the photograph colors appear untrue and the color photograph is unacceptable. The only way to avoid this situation heretofore has been to employ color negative film which reverses the order of sensitivity of the light sensitive layers.

SUMMARY OF THE INVENTION The present invention involves a new development process for the color positive release print stock or rfilm so that it can be directly exposed in a camera to ordinary daylight, and when subsequently developed it will have true blue, yellow and red colors in proper balance.

According to the invention, the concentration of reagents in the reducing developer are so adjusted that the reaction sensitivity of the exposed silver halide in the most sensitive layer is reduced while the reaction sensitivity of the two less sensitive silver halide layers is increased. The resulting color photograph has a greater resolution than has heretofore been possible to achieve with conventional color positive release print stock. This resolution is as much as 200 lines per millimeter or better. Furthermore, the new development process makes it possible to expose the color print release stock in a camera to the light of lamps in the range of 3,400 K. to 6,l00 K. without requiring color compensating filters. The new process makes it possible to employ conventional color positive release print film for microfilm purposes due to the high resolution attainable, as above mentioned. The new process makes it possible to use conventional color positive release print film for producing titles in motion picture film due to the high contrast, high resolution results attainable. The invention also makes it possible to use color positive release print film or stock for direct aerial photography where high contrast and high resolutions are required. All of these desirable results and others for using conventional color positive release stock or film are made possible by the new development process whereas heretofore conventional color positive release print stock could not be used for any of these highly critical purposes.

The process involving the invention will be explained in connection with commercially available color positive release print film such as Eastman Kodak types 5380, 5385 or 7380, 7385, and Gavaert color positive print film type #954, in further detail.

In each of the conventional color positive print films above mentioned the film has the typical multilayer structure:

(1) =Uppermost layer transparent gelatin;

(2) Top photosensitive layer-green sensitive containing silver halide and magenta dye coupler;

(3) Middle photosensitive layer-red sensitive containing silver halide and cyan dye coupler;

(4) Bottom photosensitive layer-blue sensitive containing silver halide with yellow dye coupler;

(5) Acetate or resin impregnated paper support base;

(6) Antihalation backing on support base.

Two developer solutions are used as follows:

REDUCER DEVELOPER SOLUTION The reducer developer solution employed in the development process according to the invention has the following preferred composition in approximate parts by weight:

Percent Methylparaminophenol 0.5 Parahydroxybenzene 0.5 Sodium sulphite Sodium carbonate 5 Sodium bromide 0.6 Potassium iodide 0.08 Sodium thiocyanate 0.2 Water 88.12

Potassium bromide can be used instead of sodium bromide. Sodium iodide can be used instead of potassium iodide.

COLOR DEVELOPER A color developer solution is provided having the following preferred composition in parts by weight:

Percent Diethylparaphenylene diamine 0.4 Sodium sulphite 0.5 Trisodium phosphate 3 Sodium bromide 0.2

Water 95.9

Potassium bromide can be used in place of sodium bromide.

DETAILED DESCRIPTION To use the process of the present invention color positive release print film is exposed in a conventional camera to a subject illuminated by daylight or artificial light. The exposed film is then removed from the camera without further exposure to ambient light and the following developing process is performed:

(1 The exposed film is immersed while in darkness in reducer developer solution. In this developer free metallic silver is produced by reduction in each of the green, red and blue sensitive layers. In addition, in the top, middle and bottom layers excess unexposed silver halide grains remain. Due to the presence of relatively large amounts of sodium bromide in the reducer developer solution, reactions in the top two green and red sensitive layers are accelerated or retarded with respect to the reaction time in the other layer. While the potassium iodide retards or accelerates the reactions in the bottom blue sensitive layer. The result is to balance the reaction or reduction speeds and compensate for overresponse or underresponse of the bottom layer in blue light during original exposure.

(2) The partially developed film is then immersed in a 5% aqueous solution of acetic acid for neutralizing alkalinity of the reducer developer and to arrest further reducing action of the developer, immersion time is about one minute.

(3) The partially developed film is then reexposed while still wet to artificial light of about 200 foot candles for about one minute.

(4) The partially developed film is then rinsed in water to remove any of the reducing developer solution and acetic acid remaining on the film.

(5) The wet film is then immersed for about five minutes in color developer solution to effect color development. Metallic silver with coupled color dye appears in the three layers. Magenta color images appear in the top layer. Cyan images appear in the middle or intermediate layer, and yellow images appear in the bottom layer next to the support base.

(6) The film is then immersed in a 5% aqueous solution of acetic acid to neutralize alkalinity and stop action of the color developer.

(7) The film is rinsed in water to remove acetic acid and color developing agents.

(8) The film is then immersed in an oxidizing or bleach solution for four to five minutes to convert metallic silver produced at steps one and two to silver halide which is soluble in fixing solution. This solution may have the following composition in parts by weight; this solution is an oxidizing or bleach solution:

Percent Potassium dichromate 0.5

and/or Potassium ferricyanide 5.0

Potassium bromide or sodium bromide 2 (9) The developed layers are then fixed and hardened in a fixing solution which dissolves all silver halide formed by the oxidizing or bleach solution. The fixing solution may have the following composition in parts by Weight:

Percent Sodium thiosulfate 15 Sodium sulfite 1.5

Boric acid 0.7 Aluminum sulfate 1.5 Acetic acid 1.4

Water 80.1

(10) The fixed film is then washed in water for about four to five minutes.

(11) The finished color film is then dried.

The steps in development of the color positive release film described above are basically followed in known development processes.

The essential difference occurs in the first step when halide reduction in the various layers is either accelerated or retarded with respect to each other by the addition of varying amounts of chemicals.

The resulting finished positive print has a number of unusual and unexpected characteristics:

(1) The grain size is many times smaller than in conventionally developed color positive prints, resolution being 200 lines per millimeter or better.

(2) A wide range of lighting from 3,000 Kelvin to 6,100" Kelvin can be employed without using compensating color filters.

(3) The print is produced without use of color negative film which reduces cost of photographic materials considerably in addition to eliminating the entire processing for the color negative film.

(4) The resolution of the print is high enough so that it can be used for microfilm copying, aerial photographs, title material for animated films, medical microphotography and many other applications where acceptable color prints developed by use of color negatives have heretofore not been possible.

(5) The colors of the finished photograph are more vivid and true to original colors of the photographed subject.

While We have illustrated and described the preferred embodiments of our invention it is to be understood that we do not limit ourselves to the precise construction herein disclosed and that various changes and modifications may be made within the scope of the invention as defined in the appended claims.

What is claimed is:

1. In a process for developing an exposed multilayered color positive release film which before exposure has an uppermost layer of transparent gelatin, an upper photosensitive green-sensitive layer containing silver halide and magenta dye coupler, a lower photosensitive redsensitive layer containing silver halide and cyan dye coupler, a bottom photosensitive blue-sensitive layer c0ntaining silver halide and yellow dye coupler, a paper sup port base impregnated with a member selected from the group consisting of acetate and resin, and an anti-halation backing on said support base, said process comprising immersing said exposed film in a first developer solution containing a bromide ion, thereafter exposing the film to limited reexposure light, thereafter immersing the film in a color developer solution, thereafter bleaching the colordeveloped film, and thereafter immersing the oxidized film in a fixing solution, the improvement comprising empolying as said first developer solution an alkaline aqueous solution comprising in combination at least about 0.6 percent of metal bromide, at least about 0.08 percent of metal iodide, and at least about 5 percent of a metal carbonate, said bromide, said iodide and said carbonate each being a salt of a metal cation selected from the group tofore not been possible.

2. The improvement according to claim 1, in which said process includes immersing said first-developertreated film in suflicient aqueous acetic acid to about neutralize residual alkalinity of said first developer solution, in which said reexposure light is about 200 foot References Cited UNITED STATES PATENTS 3,183,087 5/1965 Lohmer et a1. 96-22 J. TRAVIS BROWN, Primary Examiner A. T. SURO PICO, Assistant Examiner US. Cl. X.R. 96-55 

